


Topics Under Review

by relucant



Series: Grammar Games [5]
Category: Supernatural
Genre: Alternate Universe - High School, Anal Fingering, Anal Sex, Bottom Dean, Dom/sub Undertones, Enthusiastic Consent, Grammar Porn, M/M, Spanking, Spelling & Grammar, Strip Games, Top Castiel, hole spanking
Language: English
Status: Completed
Published: 2015-09-25
Updated: 2015-09-25
Packaged: 2018-04-23 04:19:47
Rating: Explicit
Warnings: No Archive Warnings Apply
Chapters: 1
Words: 6,736
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/4862888
Author URL: https://archiveofourown.org/users/relucant/pseuds/relucant
Summary: <blockquote class="userstuff">
              <p>Cas sighed.  “You aren’t an asshole.  I was mad,” he admitted.  “And still am, a little bit.  But I understand, it’s not your fault.”  He paused.  “Well, calling your teacher a shithead was kind of your fault.” </p>
<p>Dean pushed Cas up against the table, a wicked grin on his face.  “You wanna punish me?” he asked, biting at Cas’ earlobe, and Cas’ hips jerked against his.  “Teach me not to run my mouth like that?” </p>
<p>“You clearly need some discipline,” Cas murmured.  “And you’ve missed out on our lesson.” </p>
<p>“Mostly review.  Test on Monday.”  Dean drew his lips along Cas’ jaw.  “Maybe you should quiz me. Make sure I understand this shit?” </p>
<p>Cas sucked in a breath.  "You're impossible."</p>
<p>Dean grinned at him.  "My place, then?"</p>
<p>Cas scowled briefly, then exhaled, a smile quirking at his mouth.  "Fine.  But you owe me dinner."</p>
            </blockquote>





	Topics Under Review

**Author's Note:**

  * For [majestic_duck (majesticduxk)](https://archiveofourown.org/users/majesticduxk/gifts).



> fkn pulling teeth, this was. *flings porn*
> 
> for duck in honor of #teamdean'sredass <3

The next Tuesday afternoon found Cas and Dean back in the library, this time reluctantly chaperoned by Sam. 

“Kid’s got a late baseball game,” Dean explained, ruffling Sam’s hair. “Figured I’d take him over after we’re done. You wanna come watch?” 

Sam looked over hopefully, but Cas sighed. 

“I’d love to,” he said apologetically. “But my mother has declared tonight a family dinner night, and I’m a bit obligated to attend.” 

“Ooh,” Dean teased. “Filet mignon and escargot, I assume?” 

Cas snorted. “More like over-cooked steaks and boxed mashed potatoes,” he said. “But Gabriel usually brings home something decadent for dessert, so it’s worth it.” 

“Oh, man,” Dean groaned. “How much do I have to bribe you to sneak me a piece?” 

“I’ll do my best,” Cas assured him. “And next time you’re free, you’re welcome to join us. Both of you,” he added, nodding at Sam. “My parents would be pleased -- if surprised -- that I’m making friends. Though I make no promises for my siblings’ behavior.” 

“Tell Gabriel if he makes me pie, he’s cool in my book,” Dean affirmed. 

“Are they that bad?” Sam asked curiously, and Cas waved his hand. 

“Anna is wonderful,” he said. “She’s just a year behind you, in fact. But she’s a handful. And Gabe…” He sighed again. “He’s probably less obnoxious and more amusing if you didn’t grow up with him, to be fair. He does keep the house lively.” 

“That’s somethin’,” Dean agreed. “But yeah, that’d be awesome. Not a lot of variety in our house.” 

Cas smiled at them, flipping open Dean’s textbook for review. 

For once, their session only lasted the assigned hour, with Sam bent over an essay at the next table, periodically pushing the hair from his eyes. 

Dean still flirted incessantly, hooking his foot around Cas’ ankles and ostentatiously biting at his pen cap, but at 4:00 Sam’s phone beeped, and Dean shut the book with a groan. 

“We gotta go,” Dean apologized. “Wish I could take you home, but don’t got time.” 

“It’s fine,” Cas assured him. “The next bus leaves shortly from across the street, and will get me home in time for dinner while avoiding awkward family conversation.” 

“‘Kay,” Dean agreed. He leaned in to kiss Cas, and Sam made an obnoxious gagging sound. “Go wait in the car, bitch,” Dean said without looking over. 

“You are foul. Jerk.” Sam shuddered, but laughter was audible in his voice. “See you tomorrow, Cas.” He shouldered his bag and wandered off. 

“Good luck at your game,” Cas called after him, and Sam threw a thumbs-up over his shoulder. 

“I’m gettin’ spoiled havin’ you all to myself most days,” Dean murmured, brushing their lips together. 

“Me, too. Though you are at least _slightly_ less distracting in the library.” 

“Not what you said before.” He nipped lightly at Cas’ lower lip, and Cas groaned. 

“Go. Before you seduce me in public again.” 

Dean sighed dramatically, but he grabbed his bag before pressing one more brief, hard kiss to Cas’ mouth. “See you at lunch tomorrow?” 

“Okay,” Cas agreed. Dean gave him a crooked smile before disappearing out the door. 

Cas shook his head, willing his body to ignore its reaction as he gathered his books, and managed to get to the bus stop just in time. 

\--- 

Cas didn’t get a chance to see Dean again outside of school before their next Friday session, but he joined his table for lunch, tentatively at first, until he realized with surprise that he was joining in the banter. The others still teased him relentlessly -- especially Charlie and Jo -- but more and more he was able to come up with a reasonably witty retort instead of a mortified blush, and every time he did Dean beamed at him proudly. 

And Dean texted him in the evenings sometimes -- _dude, star trek marathon on sci fi channel. one of these days im gonna get u to watch with me_ \-- and they began even sneaking texts under the desks in tedious classes. (“Cas, you’re in the same _building_ ,” Charlie groaned in calculus. “You kids are grody.”) 

So on Friday, a burble of excitement tingled in Cas’ belly as he made his way to the library. Dean wasn’t there yet, so he plunked his bag onto a table in the far corner, opening his laptop. 

The flow of students past the library doors slowed to a trickle. Cas bent his head, biting a fingernail, but eventually 3:00 came and went with no sign of Dean. 

He flipped idly through his physics notes, one eye still on the door, but by 3:15 Cas had to admit that not only was Dean a no-show, but he’d missed the next bus for an hour. Gritting his teeth, he slammed a textbook open on the table next to his laptop and began typing. 

Just after 4:00 Cas began shoving his stuff into his backpack, and then Dean collapsed through the door, grinning. 

“Shit! You’re still here! Cas, I --” 

“Yes, I’m still here,” Cas cut in, acidly. “Nice of you to join me.” 

Dean strode over to the table and bent down to kiss him, but paused at the look on Cas’ face. 

“I’m sorry,” he said, holding up his hands, but his lips were still twitching, and Cas shot him a sour glare. 

“I’m glad you found something much more entertaining than our English lessons,” he muttered. 

“ _No_ ,” Dean said, finally schooling his face into repentance. “Dude. I’m sorry -- I _am_ \-- but hear me out, wouldja?” 

Cas eyed him, resolutely ignoring the way the laughter in Dean’s eyes highlighted the leaf-green. “Fine,” he conceded. “What happened?” 

Dean grinned at him again, then reached into his backpack, pulling out a sheet of paper with a 97% clearly marked on top. “I got detention.” 

Cas blinked at him confusedly. “For…?” 

“Got the best grade in my class on the verbals quiz,” he announced, flicking his quiz at Cas. 

Despite his annoyance, Cas broke into a smile. “Dean…” 

“Yep,” Dean continued, then his grin faded. “Henriksen said I must’ve cheated. Quizzed me in front of the whole class.” 

“He _what_ \--?” 

“And I got ‘em all right,” Dean continued. “Should’ve seen the look on his face.” 

“He gave you detention for… _not_ cheating?” 

“Well.” Dean rubbed the back of his neck. “I may’ve told him he’s a shithead.” 

Cas snorted a laugh, dropping his head to the table. “And you couldn’t’ve texted me?” 

“I kinda couldn’t,” Dean said earnestly, reaching for Cas’ hand. “Got Hennie last period, soon’s he saw me texting you, he told me I’d have double detention if I didn’t hand over my phone. I came over as soon as I got out. I’m real sorry, Cas, I know I’m an asshole, I just --” 

Cas sighed. “You aren’t an asshole. I was mad,” he admitted. “And still am, a little bit. But I understand, it’s not your fault.” He paused. “Well, calling your teacher a shithead was kind of your fault.” 

Dean pushed Cas up against the table, a wicked grin on his face. “You wanna punish me?” he asked, biting at Cas’ earlobe, and Cas’ hips jerked against his. “Teach me not to run my mouth like that?” 

“You clearly need some discipline,” Cas murmured. “And you’ve missed out on our lesson.” 

“Mostly review. Test on Monday.” Dean drew his lips along Cas’ jaw. “Maybe you should quiz me. Make sure I understand this shit?” 

Cas sucked in a breath. "You're impossible."

Dean grinned at him. "My place, then?"

Cas scowled briefly, then exhaled, a smile quirking at his mouth. "Fine. But you owe me dinner."

\--

Several hours later Dean and Cas were munching on spaghetti, watching curiously as Sam wolfed his plate down, his eyes on his watch.

"Somewhere you gotta be, Sammy?" Dean finally said, wiping his mouth.

"Um," Sam said, turning red. "I -- Jess invited me over. I thought --"

"Jess?" Dean interrupted. "Jessica Moore, across the street?"

Sam nodded, focusing on his noodles. "Dean, please --"

"I like her," Dean announced. He slurped up some pasta, earning a bitch-face from Sam. "Be home around midnight, yeah?"

Sam's eyes lit up. He jumped up and rinsed his plate off before grabbing his bag. "Thanks, Dean!" he called, then ducked out the door."

"Use protection!" Dean yelled, and Cas batted him on the head. "What? Kid's gotta learn responsibility."

"I thought we'd agreed that _you_ need to learn discipline," Cas murmured, tugging lightly on Dean's hair.

Dean's eyes dilated visibly, dropping to Cas' lips. "Guess we're done with dinner then?" he said with a smirk.

Cas hummed, then twisted his fingers once before picking his fork back up. "No. I'm still enjoying it."

"Tease," Dean grumbled, and Cas smiled down at his plate.

Finally they rinsed their dishes and put them in the dishwasher before trotting up the stairs.

As soon as Dean shut the door he began backing Cas towards the bed, but Cas pushed him away. "Give me your quiz," he said, holding out his hand.

"Seriously?" Dean whined. Cas just raised his eyebrow, and Dean sighed, rummaging in his bag. "Christ, you'd think you'd be _happy_ I did good," he muttered.

He thrust his quiz into Cas' hand, and Cas closed his fingers around it automatically, but he sat down on the bed, tugging Dean down with him.

"I'm sorry. I didn't mean to imply that I'm not proud of you, not happy. I'm just -- I'm not _surprised_ in the slightest."

"Yeah, 'm finally gettin' to middle school level English, I'm a real catch now," Dean muttered. "Should just be proud of yourself for haulin' me this far."

Cas stared at him for a moment, then put the quiz paper down. "Dean. I'm literally parroting -- poorly -- the things my own teachers taught me. And you pick it all up so quickly. I just -- you sell yourself so short." He looked down at the bed.

Dean rolled his eyes. "Dude, it's okay, Cas. It's cool I passed a test for once. You don't need to -- _oomph_."

Cas suddenly flipped him onto his stomach and straddled his hips, picking up his quiz again.

"This is harder than the examples I gave you," Cas murmured, trailing a hand down Dean's spine while he looked it over. "If you can get a 97% on this, I bet you could get a perfect on the test with a little more study."

Dean groaned, pillowing his face on his arms. "Yeah, but -- the test is on _everything_ we've covered."

"So I guess you should prove a point to Henricksen, hmm?" Cas pressed a soft kiss to Dean's shoulderblade. "Maybe to yourself?"

"Maybe you shouldn't be sittin' on my ass if you want me to concentrate," Dean retorted, though he made no move to throw Cas off.

Cas hummed. " _Susan's goal is running a marathon to raise money for her school._ " He made a face. "That's an intentionally deceptive sentence. You identified the infinitive phrase correctly, good -- what part of speech is it functioning as?"

"Um," Dean said. "As -- as an adverb, right? 'Cause it answers _why_ she's running a marathon?"

"Right." He smoothed his hand down Dean's back, and Dean pressed into his touch. "Now, you've left _is running_ alone."

"Well, yeah -- that's just a plain ol' verb, right? Uh -- present progressive?"

Cas sighed in annoyance, and Dean flinched. "Sorry," he mumbled. "Know I'm not --"

"No, no," Cas hastened to assure him. "I've always hated it when teachers included questions meant specifically to trip students up, rather than to test their knowledge. It's like celebrating poor teaching."

"Yeah, no arguments there. So -- it ain't a verb?"

"If the subject were simply Susan -- _Susan is running a marathon to raise money for her school_ \-- then it would be the present progressive of _to run_ , yes. But what's the subject of this sentence?"

"Uh -- well, Susan's goal, right?"

"Mm-hmm. So?" Cas prodded.

"Well," Dean said slowly, frowning in concentration, "I guess it's not Susan's goal that's actually, y'know, _doing_ the running; it's Susan."

"You're getting it. And?"

"So…" Dean went silent for a moment. "Is it like -- like what you said before, like _I like eating pie_ \-- _eating pie_ could be replaced by a noun?"

"Which would make it a…?"

"A -- a gerund?" Cas nodded, and Dean furrowed his brow. "So… _running_ isn't the action of the sentence, it's the -- the direct object? Susan's goal is running, Susan's goal is… y'know, pie?"

"Exactly," Cas said, smiling.

"Man, that's just douchey, givin' us a question like that," Dean complained. "Fuckin' Henriksen."

"I don't disagree. And yet you still understood it easily, as soon as I pointed it out."

"Yeah, yeah, 'm a fuckin' grammar genius an' all. So are we done?" Dean rolled his hips enticingly.

" _Dean_ ," Cas said, tightening his knees to still Dean's hips. "One question hardly constitutes a _review_."

"But I wanna get naked," Dean whined. He turned his head, looking up at Cas through his lashes. "Don't you wanna get naked, Cas?"

"Don't give me that look," Cas chided, but he couldn't help the grin quirking at his mouth. "Yes, I would like to get naked with you. But I very much would rather not have to _stop_ being naked with you so we can study. Especially because I don't foresee that successfully occurring."

Dean let out a long sigh. "God, you're the worst tutor-slash-not-not-boyfriend _ever_."

Cas snorted. He slid a fingertip just into Dean's waistband. "How about this," he offered. "Every question you get right, we'll take off an article of clothing. Alternating, you first, then me. We'll be done once we're both naked. Good enough motivation to get the answers right?"

Dean groaned. "You're gonna kill me," he informed Cas. "And if I _don't_ get the answer right?"

Cas paused, then he raised his hand and spanked Dean hard. It couldn't have stung much, not through the denim, but Dean inhaled sharply.

"Yeah," Dean said, swallowing once. "Yeah, that works."

"Good," Cas murmured. "Because don't forget, you still deserve punishment for mouthing off to your teacher and standing me up, making me wait. I don't think you want to get too many wrong before that."

"Jesus Christ, you sure got a mouth on you for someone next-door to a virgin," Dean breathed.

"I guess I have a muse." He leaned down, pulling Dean's shirt up just enough to press a kiss to his spine, then sat back. "We'll start off easy. Tell me what I'm doing right now, in present progressive."

"You are _driving me insane_ ," Dean hissed.

"Good," Cas said, patting him on the hip. He reached back and unlaced Dean's right shoe.

"Are you fuckin' kidding me?" Dean growled as Cas tugged it off and tossed it to the floor.

"Shh," Cas said. "Remember, more correct answers will get you what you want. Give me a prepositional phrase describing where I'm sitting."

"On my _ass_ ," Dean complained. "Adverbial, before you fuckin' ask. _Where_."

Cas hummed approvingly, tugging his own shoe off. "And if you were to make it adjectival, what would the question be?"

Dean turned around slightly, blinking confusedly. "Adjectival? So like -- who or what? _What_ are you sitting on? Or maybe _which ass_ are you sitting on?"

Cas snorted. "Bonus point for you." He pulled off Dean's other shoe, and then one sock.

"Careful," Dean muttered. "Don't wanna move too fast."

Cas ignored him. "Give me a sentence in the future perfect passive."

"I -- _what_? C'mon, Cas…"

"You know this."

Dean let out a pained noise. "Um. Soon -- soon I will be fucked by you?"

Cas _tsked_ , then spanked him hard across his right cheek.

"Ow!" Dean yelped. "Okay, okay, um --"

"Future _perfect_ passive," Cas reminded him.

"Ugh, future perfect. Fuck." Cas waited patiently, just tapping his fingers on Dean's ass. "Future perfect's like -- future-past, right? So like, you _will have fucked_ me, and so -- I -- will have been fucked by you?"

"Perfect," Cas agreed. He toed his other shoe off, letting his socked feet brush over Dean's calves. "Now a sentence in the simple past, with an adjectival preposition."

"Are you kidding -- _ouch_!" Dean jerked as Cas applied another hard smack to the other side, but made no move to escape. "Okay, okay, sec -- um -- I liked the dude _on my ass_ 'til he turned out to be a _monster_.”

Cas couldn't quite bite back a snort of laughter. "You're awfully eager to get naked with a monster you don't like," he pointed out, reaching back to tug Dean's other sock off, pressing his thumb into the arch of his foot.

"Yeah, well, 'm a sucker for punishment," Dean grumbled, turning his face back into the pillow.

"I'm realizing this," Cas agreed, trailing his fingers up Dean's leg. "Okay, last easy one."

"Last _easy_ \--"

"Give me five prepositional phrases describing your current position. Tell me whether they're adjectival or adverbial."

Dean let out a slow breath. "Okay. Well. You're sitting _on my ass_ , so -- _hey_!"

Cas spanked him again, more gently. "Stop repeating yourself. Think of new ones."

"Fine, Jesus. The guy _that I wanna be fucking_ is a complete asshole. Adjective. How's that?"

"Good," Cas said. "Four more."

"Um. And right now he's got me _underneath_ him, and _between_ his legs. Not that I mind," he added, throwing back a crooked grin.

Cas blushed, leaning down to kiss Dean's shoulder before smacking him lightly again. "Adjectival or adverbial?"

"A-adverb. _Where_."

"Perfect. And two more."

"Um. And -- and I want the body _on me_ \-- adjective, _which_ body -- to be naked and _inside me_. Are we done?"

Cas quirked an eyebrow, flicking at the juncture of Dean's ass and thigh. "Adverbial," Dean quickly added. "Where I want you. Jesus."

"Good," Cas praised. He reached back and pulled both of his own socks off.

"Surprised you ain't goin' toe by toe," Dean grumbled, and Cas spanked him again.

"Don't be rude," he chided. "Anyway, I have no desire to keep us clothed. But it's up to _you_ to remedy that."

"Or-r-r you could just tear off my clothes and fuck me," Dean offered, looking over his shoulder hopefully, and Cas snorted.

"I could. But I won't." He slipped his hand under the hem of Dean's shirt, tracing a fingertip up his spine. "What parts of speech can an infinitive function as?"

"Uh -- adverb, right? Like on the quiz. Why'd she run? -- to raise money."

"Good. What else?"

Dean thought for a moment. "I remember it can be an adjective too, but don't remember how…"

Cas hummed, scratching his nails lightly over Dean's skin. "Think of a book."

"A book? What -- oh, _to read_ , yeah? _What_ book -- a book _to read_?"

"Mm-hmm. And one more."

"Um. I know it can't be a verb, 'cause that'd make too much fuckin' sense. So a noun."

"Give me a sentence?

"I want _to be naked_ ," Dean replied immediately. "It's a -- a -- the pie thing again, right? Direct object?"

"Exactly." Cas pushed Dean's shirt slowly up his back, drawing a trail of goosebumps over the skin. He bit lightly at the back of Dean's neck as he tugged the shirt off, and Dean groaned, hands flexing in the plaid sheets. Sitting back slightly, he paused to admire the play of lean muscle over Dean's shoulders, freckled and pale in the early evening light.

"God, you're gorgeous," he blurted without quite meaning to.

Dean threw him a hazy glare. " _Not_ helpin' me behave, dude."

Cas shook himself. "We're nearly done. Concentrate."

" _Concentrate_ , says the hot guy stripping off our clothes?" Dean said incredulously.

"I can stop," Cas suggested innocently.

"And I can kill you in your sleep," Dean retorted. "Okay, hit me. Not -- _ow_!" he yelped indignantly.

"You quite literally asked for it," Cas pointed out, rubbing Dean's ass.

"Dick," Dean mumbled into the pillow.

"You seem to like it." Cas rolled his hips in emphasis, and Dean groaned at the feel of his cock, even through the layers of denim. "Tell me about the gerund."

"Um, it's an Aquarius, it likes long walks on the beach, and -- okay, okay!" he added as Cas flicked him hard. "Uh, gerund -- that's the -ing noun shit, right? Like instead of sayin' _I like to eat_ , y'say _I like eating_? Or, I dunno, _eating makes me happy_?"

"Exactly," Cas said again.

Dean twisted around to watch as Cas peeled off his own t-shirt, tossing it to the floor. Cas ignored his appreciative eyes with difficulty.

"So if the gerund functions a noun," Cas continued, returning his fingertips to Dean's back, "what's the participle?"

"The fuck you expect me to think when you're sittin' there all hot an' half-naked," Dean mumbled. Cas just dug his fingers into the meat of Dean's ass, drawing out a groan. "Um. Okay. They're, uh, they're -ing too, right?"

"Some," Cas agreed. "But not all."

"Cas," Dean whined.

"Three more questions, after this one," Cas said. "Jeans and boxers. It's up to _you_ how soon we're done."

"An' if I'm goin' commando?" Dean retorted, throwing him a smirk.

Cas raised his eyebrow, then slipped his fingers into Dean's waistband to tug the boxers up between his legs. Dean hissed, dropping his head and arching his back.

"Participles, Dean," Cas reminded him, letting go of the elastic with a snap.

"Okay," Dean said, drawing in a breath. "Uh. So -ing words, those are, um, the present participle, right? So the past participle is the -ed words."

Cas hummed in acknowledgement, then slid his hands under Dean's waist to unbutton his jeans, scrambling off to tug the denim down his legs.

"Fuckin' finally," Dean grumbled, lifting his hips to assist, and Cas smacked his ass once before tossing the jeans to the side.

"Remember, you still deserve a punishment for being rude to your teacher and standing me up," he pointed out. "Are you that eager for it?"

"Yep," Dean announced immediately, grinning. "Oh, spank me, Cas," he called over his shoulder in a high, theatrical voice, "I've been such a bad, _bad_ \-- _ow_!"

"Somehow I don't think you're learning your lesson," Cas said, shaking his head, but he couldn't bite back a laugh as he rubbed Dean's ass.

"Definitely not," Dean agreed, settling his head back on his arms. "Definitely more lessons."

" _Anyway_ ," Cas continued with amused exasperation. "So what does a participle function as?"

"Uh, lemme think. Well, the present -- the -ing shit -- know those ain't nouns, 'cause gerund. They're -- they're -- verbs, right? Progressive shit?"

"They _function as_ verbs, yes," Cas clarified. "How would you form it?"

"Fuck, uh… I forget the word you said, but _to be_? Plus the participle? So like I _am dyin'_ over here?"

"The copula," Cas agreed. "But yes, exactly." Cas peeled off his own jeans before swinging his leg around to straddle Dean's hips again, taking a moment to stroke his thumbs over the flannel-clad curves. "Two more."

Dean grumbled under his breath, earning a smack to his hip.

"So a participle can function as a verb, yes," Cas said. " What else?"

"Ugh," Dean complained into his elbows. "Um -- _-ing_. So like -- the _crying child_ or some shit, right? Which'd be an adjective."

"Exactly." He dragged the waistband of Dean's boxers slowly down, pausing to admire the play of moonlight from the window on the freckled skin, before shifting to tug them down as far as he could. Dean kicked them the rest of the way off, despite the awkward weight of Cas on his thighs.

"C'mon," Dean whined, wiggling his hips. "Last one, right?"

"I don't know," Cas said thoughtfully, running his fingertips over the silky skin. "This is an appealing view."

"I'll fuckin' appeal _your_ view if you don't get on with it," Dean growled.

"That doesn't even make sense," Cas chided, digging his fingers roughly into one cheek. "Maybe you _do_ need more practice."

"Cas, I swear to God, if you -- _hey_!" Dean yelped indignantly Cas' hand connected sharply with the bare skin.

"You aren't helping your case, Dean," Cas pointed out. He ran his finger between Dean's cheeks, pausing teasingly over his hole, and Dean shuddered.

"C'mon, _please_..." His voice was raspy with arousal, and Cas relented.

"Fine. Last one. If -ing words are the present participle, tell me more about the past participle. What it can function as, with examples."

Dean sucked in a slow breath. "Past, yeah, is -ed, except when the verb's, y'know, fucked up?"

Cas snorted softly. " _Irregular_ is the term."

"Yeah, that. So like it could be an adjective too? Like instead of the _crying_ child, you could say the, I dunno, the _frightened_ child? Or the -- the _broken_ plate?"

"Mm-hmm. What else?"

"Well, if it's -ed, then it forms the past tense, right? Y'know -- I _frightened_ the child?"

Cas _tsked_ , and Dean tensed in anticipation of Cas' hand, but it never landed. 

"Not exactly, but that's confusing, thanks to English' syntactic eccentricity," Cas admitted.

"Ooh, again with the dirty talk," Dean teased, and this time Cas did spank him, just hard enough to earn a smirk thrown over Dean's shoulder.

" _Anyway_. It's used in the perfect tenses, yes, but not the simple past. Think of the examples you just gave me. You _frightened_ the child, but --?"

"But," Dean said slowly, "I didn't _broken_ the plate, I broke it. So in the perfect… I _have broken_ the plate? _Have frightened_ the child?"

"Present perfect, yes. Past and future?"

"I _had broken_ it," Dean said immediately. "I _will have frightened_ the child."

"Mm-hmm," Cas said, drawing his fingertip in slow circles over Dean's back. "It has one last function. Your favorite."

"My favorite?" Dean echoed, twisting slightly until he could glance back at Cas in confusion. "What -- oh!" He broke into a grin. "Submissive voice, right? The plate's _broken by me_ , an' the child _was frightened by me_. Or _will be broken_ and _frightened_."

"Exactly," Cas said with a laugh. "Though I would recommend sticking to the term _passive_ in class, to avoid some awkward questions."

"Hey, I ain't ashamed of it," Dean pointed out. "Now do I _finally_ get my reward for bein' such a good little student?" He reached a hand back until he could tug awkwardly at Cas' boxers.

"I suppose it's only fair." Cas rolled off, and Dean shifted to his side to watch appreciatively as Cas finally yanked the boxers off and kicked them to the floor.

"'Bout fuckin' time." Dean eyed Cas up and down, gaze lingering on his cock, and he reached down to palm at himself, but Cas just grabbed his wrist and pushed him back down on his stomach before clambering back on top.

"Oof," Dean grunted as Cas' weight landed on his thighs. "Heavier'n you look, y'know that?" His voice was teasing, but there was a nervous hitch to it, and Cas was hit by another wave of hesitation.

"Dean," he said, then cleared his throat. "You -- I mean -- you know we don't have to --"

Dean threw him a disbelieving look. "Dude, last I checked, _subtle_ wasn't exactly one of my best qualities."

Cas flushed. "No, but -- like you said, I'm 'next-door to a virgin', I -- I don't know what I'm even _doing_ , and --"

"Dude," Dean said again. He twisted around until he could prop himself up on his elbow. "You really think I do this with all my spare time or somethin'? I mean, yeah, it ain't my first rodeo, but I'm not exactly a pro either here."

Cas relaxed slightly, but still looked unconvinced. "But -- but are you sure you want _me_ to --"

"Cas," Dean interrupted with an eloquent eye roll, "Promise, if I want you to stop, I'll say somethin'. But I swear to God, you don't start bruisin' my ass in the next thirty seconds I'm gonna bomb that test outta spite."

Cas' eyes darkened. "Bossy, aren't you, for someone in your position?"

" _Yes_ ," Dean insisted. "Thought you were supposed to teach me a lesson."

"I thought I had," Cas pointed out. He rubbed the smooth skin of Dean's ass for a moment, then smacked it sharply and Dean sucked in a breath. "I guess I failed."

"If that's all you got, then yeah," Dean rasped. "You even lift, Cas?"

"No." He spanked Dean three times in quick succession, watching in fascination as the skin turned pink, visible even in the pale moonlight.

"Fuck," Dean breathed.

"Maybe," Cas said, spreading Dean's cheeks and trailing his thumbs between them. "If you're good."

"I'm good," Dean gasped. "Christ, 'm good."

"At some things," Cas agreed. He licked his index finger and rubbed it gently around Dean's rim. "You're good at being infuriatingly attractive. You're good at seducing virginal private school boys."

"I did not _seduce_ \--" Dean began indignantly, but Cas smacked him with his free hand, and he turned his face back to the pillow with a groan.

"You're good at English grammar, though you're _not_ good at acknowledging that." Dean huffed but didn't argue. Cas leaned down to brush a kiss to the small of Dean's back, then spanked him hard across his sit-bones.

Dean cried out, and Cas froze, hands hovering over the warm pink flesh. "Dean? Is this -- do you want to --"

"If you say _stop_ , so help me, I will kill you," Dean growled, throwing a hazy glare over his shoulder.

"So demanding." Cas rubbed Dean's cheeks for a few moments, then without warning he laid a sharp slap to each side.

"Fuck, yeah." Dean's hands flexed in the bedsheets, and he spread his legs slightly. "C'mon, baby, more…"

Cas acquiesced, settling into a relentless rhythm of hard, open-hand blows interspersed with quick smacks to already sore spots. He watched in awe as Dean's ass turned from milky white to pink to burning red, and every shuddering gasp and groan he drew out seemed to go directly to his dick.

"You're so _beautiful_ ," Cas murmured, spanking him hard on each side. "You're _perfect_." He dug his fingertips into the hot tender flesh, massaging roughly and spreading his cheeks apart. He paused, then brought two fingers down over Dean's hole.

"Fuck!" Dean yelped, jerking away instinctively, and Cas flinched.

"I'm so sorry -- I didn't --"

"Do that again," Dean whispered through unsteady breaths.

"Dean -- are you sure you --"

" _Again_ ," Dean insisted. He spread his legs further and twisted the pillow in his hands. "Harder."

Cas hesitated, but brought his fingers down again, more sharply.

"I said _harder_." Dean shifted forward until he was on his knees, bent over in clear invitation.

"Jesus," Cas said in awe. "Look at you, begging for it."

"Yeah," Dean rasped, muffled in the pillow. "Gonna -- gonna _do_ somethin' about it?"

In response Cas spanked his hole twice in quick succession, and Dean hissed and shuddered, but didn't pull away. Pressing his thumb against the slightly puffy skin, Cas leaned forward until he could rub the length of his cock between his cheeks. Dean whimpered, but he pushed back until it dragged over his rim.

"Is that good?" Cas asked, grinding his hips, and Dean moaned.

"So good." Dean tried to shove himself back, desperate for more friction. "C'mon, Cas, fuck me, fuck me…"

Cas stilled him with a hand gripping his waist, then spanked his hole with the head of his dripping cock. "Patience," he chided. He reached down to gently finger at the swollen skin, frowning thoughtfully. "Dean, are you sure you're not too sensitive? I really _don't_ want to hurt you…"

"Cas, 'm _askin'_ you to," Dean said, affectionate exasperation under the rasp of arousal in his voice. He reached over to fumble in the nightstand, then tossed the bottle of lube and a condom back to the bed. "Just don't, y'know, skimp on the lube, maybe?"

Cas snorted softly. He clicked open the lube, coating his fingers liberally before drizzling more directly between Dean's cheeks. Dean yelped at the shock of cold, but it turned into a low groan as Cas began rubbing it into the tender flesh, working his way towards his hole.

"Oh, fuck, yeah," Dean groaned as Cas finally pressed a slick fingertip inside. "Fuck, your fingers, baby, so _good_..." He tried to push back onto Cas' finger, but Cas held him still, slowly sliding his index finger in and out until Dean's body relaxed around it before adding a second.

"God, you're _killin'_ me," Dean complained, and Cas spanked him with his free hand, the slap of slick skin echoing obscenely.

"I can stop, if you like," Cas pointed out, but he pushed in a third finger before Dean could retort.

He worked three fingers in and out, twisting and stretching, until Dean finally propped himself himself on his elbows to glare back at him.

"Cas, 'm _ready_ ," he begged, shamelessly spreading his legs. "C' _mon_ , you fucker, c'mon…"

"That's impolite," Cas admonished him, but he spread his fingers one last time, and Dean's head dropped back to the pillow. "Um," he said, carefully withdrawing his fingers. "Do you -- do you want to be on top again? So I don't, you know, hurt you?"

Cas half-expected another eye-roll, but Dean just shook his head. "Like this. Wanna feel it." He threw a crooked grin over his shoulder, watching with half-lidded eyes as Cas tore open the condom wrapper and rolled it on, then slicked up his dick, pressing it to Dean's hole. "After all," Dean continued breathlessly, clearly trying to keep still, "s'the weekend, not like I gotta sit on a hard-ass desk tomo- oh fuck, fuck, _fuck_." His words trailed off into a garbled moan as Cas finally pushed himself inside.

"Fuck," Cas echoed brokenly, his self-control finally crumbling at the edges.

"S'the idea," Dean croaked. He arched his back, taking Cas deeper. "God, baby, so _good_..."

"You're so -- so _hot_." Cas dropped his head, trailing his hands down Dean's sides. "Inside and out, so -- so --"

"Pot, kettle," Dean gasped. "B-black."

Cas pulled out slightly, and Dean whined.

"C'mon, Cas," he begged. "Feel so good, c'mon, just _fuck me_..."

"I'm not -- not going to last," Cas said, gripping Dean's hips in futile attempt to keep him from shoving himself back onto Cas' cock.

" _Good_ ," Dean growled. "Been fuckin' teasin' my ass for _hours_."

"I don't think I'm _teasing_ your ass right right now," Cas pointed out breathlessly, grinding his hips in emphasis.

Dean whimpered, knuckles going white in the bedsheets. "Fuck, baby -- I think you're gonna -- you're gonna make me come just on your cock…"

Cas groaned, finally giving up on holding back. He pulled out nearly all the way, tightening his fingers on Dean's hips, then slammed in as hard as he could. Dean sucked in a long breath, then let out a wail.

"T-too much?" Cas stilled himself with effort.

" _More_ , you dick," Dean growled. "So close, baby, so close --"

"M-me too, Dean, me too…"

"C'mon, then, fuckin' -- fuckin' _harder_..."

Cas grabbed Dean's thighs, pulling him up farther, and drove in relentlessly. His cock hit Dean's prostate with every thrust, and Dean dropped his head, demands devolving into an endless garbled litany.

"Yeah," he finally managed. "Oh, fuck, fuck, Cas -- gonna -- gonna --"

"Do it, Dean," Cas bit out. He slapped Dean's ass hard and then fucked in deep, and Dean locked up, coming with a broken cry.

"Oh, _fuck_ ," Cas groaned. Dean's hole clenched around his cock as he shuddered with aftershocks, and the tight wet heat underscored by Dean's high desperate gasps finally pushed him over the edge.

"H-holy -- _shit_ ," he choked as his cock pulsed inside Dean, still rolling his hips shallowly. "Dean -- fuck -- _Dean_ \--"

"Fuck," Dean echoed, muffled into the pillow. "Jesus Christ, Cas."

Cas' knees finally gave out, and he slumped over, pressed against Dean's sweat-slick back with his cock still buried in his ass.

"Omph," Dean complained, flopping into the bed. "Heavy, dude."

"Am not," Cas mumbled, but after a few moments he drew back and pulled out, tying off the condom before flinging it to the corner.

"Jesus," Dean croaked, reaching back to touch his ass. "Jesus."

"I," Cas began, curling up a few inches away. "That was -- was that --"

"Fuckin' _awesome_ ," Dean affirmed with a grin. "But now _you_ get to lotion up my ass."

Cas smiled. "With pleasure." He fumbled for the bottle of hand lotion on the nightstand, squirting a glob into his hand, and then curled in closer. Dean yelped at the first shock of cold on the hot tender flesh, but it melted into a happy rumble as Cas rubbed it in.

"Fuck, feels nice." Dean wriggled contentedly under Cas' fingers, and Cas carefully smoothed his fingers over the sore spots.

"Dean?" he finally said.

"Mm?"

Cas paused, trying to think of the right words, before finally blurting, "Why -- why do you like that?"

Dean was silent for a moment, and Cas bit his tongue. "Not that I'm complaining," he hastened to add. "Or think it's weird. I'm just… curious."

"Yeah, first partner you have an' you get stuck with the kinky freak?" Dean teased. "Lucky you."

"I think so," Cas retorted. "And again, _not_ complaining. Nor do I think you're a 'kinky freak', as you say."

"Gimme time," Dean said, tickling him lightly, then fell silent, and Cas was about to let it drop when Dean spoke again. "Used to kinda freak me out, y'know? Like what kinda weirdo likes to be _hurt_? Figured there was somethin' wrong with me, or that my dad…" He paused again, chewing on his lip. "Like, my dad -- he didn't _beat_ us, y'know, but --"

Cas raised a dubious eyebrow, but Dean just shook his head.

"No, b'lieve me, I know my dad ain't up for father of the year or anything, but it wasn't like that. But he's never been around much, an' half the time he _was_ around he'd be drunk and yellin' about somethin'. And I'd just ignore it 'til he calmed down, but Sammy'd get up in his face, and then I'd get between 'em and Dad'd get up in _my_ face, yadda yadda. So yeah, he smacked me around a couple times -- nothin' bad, dude, before you go all scary on me. But I think it scared _him_ more'n me, so he'd actually be nice to me for a few days before he left again. So I used to think there was some sorta fucked up Oedipus shit goin' on in my fucked up head."

"Dean," Cas whispered, but Dean just hip-checked him lazily, laughing as Cas nearly tumbled off the bed.

"Nah, lemme finish. That was awhile ago, before I ever, y'know, experimented with it much or anythin'. And when I _did_ , thank fuck, let me tell you, I was _not_ thinkin' of my dad."

Cas snorted, and Dean grinned at him. "So now I figure, fuck it, y'like what y'like, right? Like, yeah, it hurts, but in this good, weird, really fuckin' hot kinda way. And then, I dunno, when it gets to the good stuff, the pain makes the good stuff _real_ fuckin' good. I guess the -- what's the word -- the juxtaposition?"

"Hmm," Cas agreed thoughtfully. "That makes sense."

"And I mean, c'mon," Dean said, rolling over carefully until they were facing each other, "big picture, s'pretty tame. I like it, you like it, no one's gettin' hurt who doesn't want to --" He stopped, visibly reviewing his words. "Wait, you -- you _did_ like it, right? I mean, you _seemed_ to, but if ain't your thing, we don't gotta -- _ow_!" he yelped as Cas dug his fingers into the tender flesh of his ass, but he just squirmed away, laughing.

"Yes," Cas admitted, pulling Dean back in. "I mean -- it's confusing. I want to make you feel good, not _hurt_ you. But then you _liked_ it, and then I wanted to hurt you _more_... It -- it's strange, but very arousing."

Dean grinned at him and kissed the tip of his nose, then rolled over onto his back.

"I can see it now," he proclaimed, throwing his arms wide. "Twenty years from now, legendary dom Castiel Novak. Someone asks you how you got started down the road to depravity. And you'll push your nerdy little glasses up your nose -- 'cause you'll still be a nerd, leather pants an' all, and you'll have to be like 'well, once I knew this kid who sucked at English grammar, and' -- ow, Cas, get _off_!"

Cas climbed on top of him, digging his fingertips into Dean's ribs until Dean threw him off, laughing breathlessly.

" -- and it was all downhill from there.'"

**Author's Note:**

> find me on [tumblr](http://relucant.tumblr.com) or [twitter](http://twitter.com/relucanting).
> 
> I'm nice.


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